


Biological Prerogative

by setoboo



Category: Katekyou Hitman Reborn!
Genre: BAMF Sawada Tsunayoshi, F/M, Future Fic, Genderfluid Mists, In the most convoluted manner possible, M/M, Mafia Boss Sawada Tsunayoshi, Misty-Sky Tsuna, Multi, Oral Sex, Semi-Public Sex, So he's gonna get one, The Mists are kinky guys, Threesome - F/M/M, Tsuna needs an heir, Unconventional Uses for Dying Will Flames
Language: English
Status: In-Progress
Published: 2019-02-27
Updated: 2019-02-27
Packaged: 2019-11-06 14:36:04
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,084
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17941577
Author URL: https://archiveofourown.org/users/setoboo/pseuds/setoboo
Summary: After a fight with Nono regarding Tsuna's lack of heirs to the Vongola throne, Tsuna makes a decision to rectify the situation. Granted he could have picked an easier manner in which to do it, but when has Tsuna's life ever been normal?And if he plans to have a little fun while he goes about getting knocked up, well that's just his prerogative.





	Biological Prerogative

If Tsuna wasn’t an avowed peacemaker he would currently be punching his grandfather in his stupid, smiling face.

“My boy, really now. What was wrong with the young Cavallone?” Nono asks with confused exasperation. Apparently unaware of the fact that Tsuna is about ready to throw himself over his ornate desk and sock the old man in the jaw the longer he continues talking. “She’s a lovely young lady, and I was under the impression you favored the Cavallone family.”

Tsuna can’t stop himself from spluttering in outrage. “Chiara Cavallone is twelve, Nono! I’m twenty-five!”

“Yes, yes -” Nono waves his hands dismissively. As if thirteen years of difference is negligible in the grand scheme of things. “- she is a tad young still, but given a few more years to mature I’m certain she would make a lovely wife. Her age is not an issue if that is what you are worried about. All it would take to set the betrothal is her mothers signature and Don Cavallone’s agreement, which considering how close you are with him - I’m sure he would consent to the match happily.”

“I’m not marrying Dino-nii’s third cousin!” He slams his hands on the desk to make his point. Which causes Coyote Nougat and Ganauche III - who appear to be Nono’s bodyguards for the day - to flinch slightly at his show of temper. Tsuna has built a reputation for being in control of his emotions, and this may very well be the first time anyone outside of his own Guardians has seen him lose his cool in years. “I have been patient with your attempts at matchmaking so far  _ grandfather _ .” He hisses the name like a curse. “But I will not have you dragging prepubescent girls to my gala’s and attempting to foist them on me. Do you know how embarrassing it was for me to apologize to Dino about this? Chiara has rarely left the Cavallone estates her entire life, and then she gets dragged to a party and told to impress me so she can become my wife! Do you know how terrified that girl was?” 

Nono sighs and sends Tsuna a look that speaks of regret. But Tsuna has had years to become accustomed to his grandfather's brand of manipulation and gives the look the same amount of credit he gives Mukuro when he catches the Mist cackling about  _ ‘definitely not planning the demise of some Vongola-traitor’.  _

_ (His Mists take keeping the Vongola loyal and corruption-free very seriously. More seriously then Tsuna is comfortable with sometimes. He regrets making Mukuro and Chrome the duel-head of internal security more often than not, but they are dreadfully good at the job.) _

“I apologize for causing the young lady any undue stress.” Nono says contritely. Tsuna just glares harder at the attempt at appeasement. He doesn’t need his intuition to know Nono is in no way actually feeling contrite. “However I’m afraid you are swiftly running out of options, my dear boy. I have introduced you to a dozen or more suitable candidates for the title of Lady Vongola and you have shot down every one of them immediately. At this point your options are to bring in a civilian or to start looking at other countries for a wife. Because I do believe you have turned down every available woman the Italian Mafia has to offer.”

Tsuna growls and rakes his hands through his hair to stop him from doing something stupid. Like tossing his grandfather out the second-story window. “I do not _ need  _ a wife, grandfather. I am busy enough keeping my own from destroying the manor on a daily basis and instilling reformations to the Mafia. I don’t have time for wooing someone. Especially not a  _ twelve-year-old-girl _ !” 

Nono holds his hands up placatingly and smiles in that grandfatherly way that Tsuna has learned to equate with unpleasant topics. “Now, now my boy. I’m sorry I seem to have upset you, but this is about more than just finding a pretty wife for my grandson. I’m trying to help you ensure the future of the Vongola. In my own clumsy way at least.” He says with a laugh so sugary and fake it makes Tsuna’s teeth ache.

The current Vongola head hums and leans back in his plush seat, crossing his legs and fixing his grandfather with an amber eyed look that speaks of understanding. “Children.” Tsuna finally states plainly, narrowing his Flame- tinged eyes at his grandfather and enjoying the way both Coyote Nougat and Ganauche III flinch at the casual show of his power. “You’re talking about children.”

Nono claps his hands and nods. “Yes, while I would love for you to find someone to love and settle down with - I’m afraid children are another rather important part of being the head of Vongola. I’ve been patient with letting you do as you please, you are Decimo after all, but even you must admit it’s starting to look a little worrisome that you have no heirs yet.”

Tsuna doesn’t reply to that. Because it is true.

He’s twenty-five, rapidly edging on twenty-six in a few short months. Nono had three heirs born before he turned thirty. The fact Tsuna doesn’t have a single heir, blood-related or not, is likely causing some not-so-minor panic to the Flame-Mafia as a whole. 

He can see where his grandfather is coming from with trying to set him up with woman now. The woman aren’t the important part, except maybe to the more catholic inclined portion of the Mafia. It is the children that those woman could bare him that is what Nono is after.

_ (He purposely ignores how his grandfather somehow thought he would be willing to sleep with a little girl - in a few years or not - to simply create an heir for Vongola. If Tsuna thinks about it too hard he’s still likely to actually punch the old man _ .)

‘’I understand that some people are a little worried about my a lack of heirs.” He gives the old man a bone and acknowledges the problem, but carries on immediately before Nono can seize on the opening. “However the way you have gone about trying to  _ ‘fix’ _ this is unacceptable. I have had very good reasons for turning down each one of the woman you’ve brought me - Including their age. I will have to firmly  _ demand  _ you stop trying to set me up, Nono. As well as make reparations to the Cavallone Family for making such gross demands on my behalf.” 

Tsuna notices Ganauche III smirk for one hot second before it is hidden behind his usual placid smile. Nono’s Lightning often reminds him of Takeshi, all easy grins and a sunny disposition that hides something underneath. Tsuna doesn’t let himself linger over what could have amused Ganauche so much. His intuition tells him it is nothing harmful to him or his own, and so he lets it go without remark.   


Nono gives a put-upon sigh but nods to Tsuna’s demands. “I suppose I do owe the young lady an apology if she was truly that upset by the meeting. It was never my intention to scare her, you understand.”

“But she was scared, regardless of your intentions grandfather, and I believe the Cavallone should be given more than just an apology. I know you used  _ my name _ to force the meeting without my permission, and Don Cavallone was extremely displeased about the deceit.” 

That was putting it mildly. Dino-nii had been  _ livid _ when he found out that his young cousin was coming to the gala apparently at Tsuna’s request. The Vongola Decimo hadn’t managed to get past saying hello to his brother before he was being grilled at whip-point about why he’d insisted on Chiara coming. The girl might have been three generations removed from the main branch of the Cavallone family, but Dino is a family man through-and through. With a Sky’s possessive tendency to protect all those under his span tooth and nail from any threats. Dragging one of the youngest members of the Bronco’s family straight into the maddened heart of Mafia politics was a sure fire way of meeting the business end of his whip. Which Tsuna had only just barely managed to dodge before he figured out what the hell his brother’s problem was - and then joined Dino’s righteous anger at Nono’s audaciousness as soon as the issue was cleared up. 

At least he’d gotten to meet Chiara - though he would have rather it been under better circumstances. She was a sweet kid, and  _ obsessed _ with ponies. Which Tsuna wasn’t sure if he should chalk that up as a normal thing for girls her age, or a Cavallone thing. However, she was only about as bad as Lambo was about collecting cow-print clothes and cow-themed nick-knacks. So he found it more cute than anything else.   


Thankfully he managed to foist the twelve-year-old onto Lambo and I-pin and gotten her out of the Gala-hall before anything happened. Dino probably  _ would _ have killed him if Chiara had stuck around and been witness to Tsuna’s Guardians ending the party by killing a dozen would-be assassins and blowing out a load bearing wall in the process. 

It was a fun night for everyone involved.

“I...see.” Nono says after a moment, as if he is surprised by the fact that Dino would be upset at being lied to. Sometimes Tsuna has a very Reborn-like compulsion to shoot at people who are being stupid, and he has to physically stop himself from reaching for the gun tucked underneath the lip of his desk. 

_(It’s not even his gun - It’s one of the hundreds of weapons Reborn has hidden around the manor._ _But that hardly stops the impulse to use it to shoot a warning shot next to Nono’s empty head.)_

“Yes, a public apology and whatever Dino-nii feels he is owed for your lie. He would have refused to let her come if it had been anyone else but me asking, and add to the fact that she was almost put into danger unnecessarily. I think they deserve physical recompense.”

Ganauche III has to actually cover his mouth to hide the grin on his face, and Tsuna is the only one who sees him do it. Nono and Coyote both have their backs to the younger Guardian. Trusting the Lightning to guard the door. So it is just the current Decimo who is treated to the grin, and the oddly thankful gleam in russet-brown eyes.

“Very well, I will speak with Don Cavallone about this when I have a chance-” Oh, Tsuna knows what that means, that's Nono’s way of saying he’s going to have a _ senile _ episode and  _ ‘forget’ _ to do it. No dice. Tsuna is going to call Dino-nii as soon as his meeting is over and inform him of Nono’s promise of repayment. “-however we have gotten off track I feel. This is about you having heirs, my dear boy. Which we both agreed is important.”

Tsuna said no such thing, but he’s learned to pick his battles. “I understand it’s important grandfather, but inviting strangers into my home puts my family in danger. I am not going to pick a random woman off the street and make her have my children. No matter how important you think this is.”

He doesn’t have to say that is almost  _ exactly _ what Iemitsu did to his mother. He will not be that same kind of man. The kind who beds a civilian just to ensure the bloodline goes on.

“Then perhaps you should look closer to home.” Nono responds back with enough good humor to have Tsuna instantly weary. 

“Pardon?” 

“If your issue with all my choices is that they are strangers, then maybe pick someone you trust! You have a number of lovely young ladies in your own family that adore you. I’m sure one of them would be willing to carry a child for you, even if they don’t want marriage. Your Mist is particularly pretty, and since she is Flame-active her chances of carrying a Sky-Flame would be higher than your other lady-friends.”

Tsuna feels his jaw drop at his grandfather’s words. 

“ _ Chrome? _ ” He strangles out the name, feeling a surge of almost-panic settle into his stomach at the idea. “My Chrome?”

He feels a tendril of Mist brush against the back of his mind. Feels how Chrome answers the call of her name without hesitation. He immediately floods the connection with fondness for her and annoyance at Nono, apologising for worrying her. Chrome’s Mist Flame hums in understanding and fades away with a gentle caress against his own Flames. Back to whatever she was doing before he called to her in his panic.

Nono nods eagerly at Tsuna, thankfully unaware of Chrome’s momentary presence. “Yes, while a wife would be preferable to keep some of the more traditional minded of the Familgia’s in line. There have always been exceptions made for Sky’s and their Guardians. No one would be surprised if she bore you a child or two as part of her duties. My own Guardian - Ganauche the First - bore my first son for me.” Tsuna is surprised by this fact. Nono rarely speaks of his sons and Tsuna was under the impression that they had all shared the same mother, except for Xanxus of course. 

The fact Nono referred to Federico's mother as ‘ _ the First _ ’ also implies that the Ganauche in the room - being the third - is a replacement for two other previous Lightning Guardians. Yikes. No wonder he is so young compared to Nono’s other Guardians. 

Still….

“I’m sorry grandfather, but that option is not going to happen.” He won’t tell the old man why. Refuses to out the fact his Second-Mist has illusionary organs, when such information could be used to hurt her. Either intentionally or not.

He also can’t even imagine what kind of stress that would put on her and Mukuro. They are both terrifyingly powerful Mists in their own right, but the idea of Chrome’s fragile internals being kicked and pushed against by a baby for nine months makes him nauseous to even think about. He doubts it’s outside of their ability to do, but he wouldn’t dare ask it of them. To ask Chrome to share her body with a child would also need to include Mukuro in that conversation. As they share their bodies with each other the same way other people might share clothes. Back and forth until even they aren’t sure who the original belongs to anymore. 

Tsuna doesn’t mind, and lets the Mist pair do as they please. Even if it means that sometimes he has no earthly idea which of his Mists he is talking too if they meet face to face. 

“Tsuna.” Nono finally says flatly, a flare of burnt umber in his eyes and a wash of Sky Flame surges from the older man. Tsuna doesn’t hiss in outrage like he wants to, but he feels his own Sky Flames bubble under his skin at the small show of force. This is  _ his _ home now -  _ not Nono’s  _ \- the older Sky has no right to be trying to force his will here. 

He takes comfort in the fact he feels no compulsion to actually listen to Nono’s words, despite the Sky Flames trying to push Harmony on him. 

“You need to start thinking of the family, young man! I don’t know what you are going to do if you’re planning to turn down even your own Guardians! Your only options left is to grow a child in a lab or become a woman and carry them yourself!” Nono throws his hands in the air, obviously at the end of his patience with Tsuna’s unwillingness to listen. 

“Your concerns have been heard, Nono.” Tsuna spits, voice more poisonous than Bianchi’s cooking. “I’ll have someone come escort you to your car.”

Nono huffs and stands up, Coyote Nougat hovering just behind the older man and practically vibrating in offense for his Boss. “No need, _ my Guardians _ are perfectly capable of performing their duties.” Tsuna almost howls in outrage at the unsubtle dig at his own Guardian’s abilities. “I’ll see you again, Decimo.”

Nono wanders out of the door without a backwards glance. Coyote Nougat on his heels. Tsuna bares his teeth at their back, and reaches through his own Flames for the twined thread of Mukuro and Chrome. They acknowledge him immediately and eagerly flow through the manor at his request to follow Nono and ensure the old man makes it to his car, and makes no unnecessary stops along the way. 

“Decimo.” The voice of Ganauche breaks him from following his Mists path through the house. He turns to the blonde and black haired man. Hardly in a mood to listen to anymore of Nono’s nonsense, even from the mouth of one of the man’s more agreeable Guardians.

“Thank you.” Ganauche surprises him by bowing low from his spot by the door. “My sister would have never forgiven me if Chiara had gotten hurt. Thank you for getting her home safely, and for ensuring the family will receive reparations for Nono lying to them.”

Tsuna blinks in momentary surprise, before his annoyance is washed away by understanding. “Cavallone!” He declares with glee lighting his eyes as he points to the older man with a triumphant grin. “I knew it! I knew you were a Cavallone!”

Ganauche gives him a wry grin and nods. “Just as distantly related as little Chiara is I’m afraid, but I’m Cavallone-blooded through and through. So you know how serious we are about family. My cousin was right to trust you Decimo. I’m glad someone else in the alliance sees family as more than just connections and blood-ties.” 

Tsuna waves off the kind words, though he will admit his fondness for Ganauche III increases a little knowing he is truly a Cavallone. He’s always had his suspicions, considering how similar the man’s natural coloring _ (when he’s not dying part of his hair black),  _ bone structure, and attitude is to Dino’s own. The fact his Lightning Flame has that same bright Sunny edge that Dino’s Sky has also helps to support the claim. 

He feels a sudden tug at his mind as Mukuro and Chrome send him a thread of alarm that Ganauche is not to be found with Nono. The two assuming the Lightning has managed to slip away for some nefarious plot. He quickly soothes the two wordlessly, letting them know he is aware the third of the trio is missing. 

“My own have noticed your absence, Ganauche.” He tells the Cavallone man, who nods in understanding and says his own goodbyes.

“Then I’ll take my leave Decimo. It’s been a pleasure.”

The Lightning trots out of the room, and Chrome lets Tsuna know the moment he rejoins the other two. Some lie on his lips for his absence that the other older men accept without question.

Tsuna isn’t even surprised when Mukuro appears in his office in a billow of Mist Flames half a minute later. Chrome obviously left to watch over Nono’s exit now that all three of the men are within her sight. 

“ _ Darling _ ,” Mukuro purrs as he leans over the edge of Tsuna’s plush chair and puts himself right in the Vongola heir’s face. Tsuna feels himself relax at the invasion of his space. Despite Mukuro being one of his most lethal Guardians, he trusts the blue-haired man without question  _ (much to the combined disapproval of almost everyone outside of Tsuna’s own) _ .

“What has your dear grandfather done to earn such ire from you now? It’s highly unusual for you to sick us on the old man. Not to mention you called for Chrome all in a tizzy not but a few minutes earlier.” Tsuna sighs as Mukuro reaches up and cups his cheek, intent on getting Tsuna’s attention and being as touchy-feely as he can about it. “We worry, darling.”

Oooh, such a low blow. Mukuro knows he can’t resist emotional manipulation from his own. 

“Nono is the reason Dino-nii was using me for target practice last night.” He admits to the male-half of his Mist set. “He invited Dino’s distant cousin, the little blonde girl in the green dress, to the gala in some attempt to play matchmaker.”

Mukuro’s agitation is almost tangible. “The horse-obsessed one? She was barely more than a child!”

“That’s what I said. Or well...yelled. It’s been taken care of Mukuro. Hopefully there should be no more matchmaking attempts from Nono.” He leans into Mukuro’s faintly chilly palm and gives an amused hum as he slyly says “I also may have demanded he make a formal public apology and give the Cavallone reparations for bringing Chiara to a gala that had - you know - assassins at it.”

“Mmmm” Mukuro hums in delight. “We do so love seeing prideful men being forced to confess their sins for the world to see. We’ll need to record it for posterity.”

Tsuna laughs before he leans forward with a conspiratorial grin that immediately catches his Guardian’s attention. “I also learned a new useful little tidbit.” He teases.

“Come now darling, don’t leave us in suspense.” Mukuro slides his hand under Tsuna chin, using his fingers to tilt the Decimo’s face upwards and closer to his own then it already was. Causing their breaths to twine together on each exhale. Lips a hair’s breadth apart.

“Mmm, so it appears that Ganauche III is actually a Cavallone by blood. The girl from last night is his niece. He was terribly amused by me demanding atonement on behalf of his family, and not very pleased by Nono using her for his games. The reason Ganauche wasn’t with the other two is that he stayed behind to thank me.”

“ _ Well _ -” Mukuro draws out the word with a fox-like smile spreading across his face, his far-too-clever mind already starting to make plans with the new information Tsuna just gifted him with. “-Now that  _ is _ interesting. Loyalty to family ahead of Famiglia. We will need to make note of that for future interactions.”

“Best not to hurt him Mukuro. Dino-nii will probably be offended.”

“Of course not, darling. We know better.” Tsuna give the Mist a bland look and a raised brow, not believing a word out of his mouth. “Mmmmm, your lack of belief wounds us.”

“I'm sure.” He drawls out the words. “Now that your curiosity is sated - can I help you with anything else, my own?” Tsuna is not even attempting subtly as he drags the edges of his flames along Mukuro’s own in a blatant invitation. Eyes blazing amber. 

“We can think of a few things.” Mukuro murmurs. Finally pulling Tsuna into the kiss he’s been teasing for the past minute.

Tsuna makes a pleased ‘Mmmm’ and sinks into the soft pressure eagerly. More than happy to have a way of working out his frustrations from the meeting in a more pleasant way. Mukuro has eager hands in his hair and Tsuna responds by dragging Mukuro into his lap for the moment. Forcing the Mist to straddle his legs and bend down to continue kissing. 

Tsuna feels reality warp around him as his chair sudden morphs underneath them into what seems to be a western style bed. Thankfully just as plush and opulent as his chair had been. He eagerly lays back, allowing Mukuro to stretch across his body and cage him into the silk sheets around them. Kisses growing heavy and lingering longer and longer. 

He moans softly in between kisses, enjoying the warmth suffusing his whole body as Mist and Sky blend together in harmony. Mukuro’s breathing comes harsher but he doesn’t move past kissing. Doesn’t grind down despite how Tsuna can feel the other man’s erection against his hip. Tsuna smiles and indulges the male-mist. Kisses back with lingering pressure and teasing nips, even darting his tongue out a few times to swipe at the spot his teeth keeps catching in their makeout session. 

Mukuro groans hungerly and finally opens his mouth enough for them to deepen their kiss. Tongues tangling and lapping at the soft spots inside their mouths, until the need for air forces them apart. Mukuro isn’t willing to leave for too long though, only the half second he needs to pull in a shaky breath before he dives back down. His mouth desperate, like that one second of no contact physically pained him. Tsuna is light headed and dazed from the lack of air - but he wouldn’t push Mukuro off him for anything at the moment.

Tsuna has to anchor himself by grabbing Mukuro’s hips in a bruising grip as the world spins slightly, but he doesn’t force Mukuro to grind against him as he wants to do. He knows what the blue-haired man is waiting on and he can be good. He can be content with the warmth of soft lips and harmony for the moment.

“Bossu” Chrome is a welcome presence that appears, quiet as a mouse, at the foot of the Mist-constructed bed. “They’re gone. We made sure they left.”

Tsuna has to turn his head to escape Mukuro’s hungry mouth so he can answer her. But that just lets the male-half of the pair move on to start nipping at his exposed neck. “Th-thank you, my Chrome.” He pulls one hand off Mukuro’s hip and holds it out to the woman, asking her to join them without words.

Chrome gives him a soft smile and take his hand, letting herself be pulled into the tangle of limbs with a spark of heat obvious in her purple eye. 

Tsuna eagerly kisses her once she is close enough, and Mukuro is no longer content to keep his touches chaste with the addition of his other half to the bed. Hiking Tsuna’s shirt up enough that he can start to kiss across his chest and nip at pink nipples until they harden, Tsuna cries out at the movement and Chrome takes advantage of his open mouth to demonstrate her own technique for kissing. Swallowing all the sounds he makes as Mukuro teases his chest ruthlessly. 

Never should have let the sadistic bastard find out he was sensitive there. 

But it feels good. His mouth open and hungry for Chrome, and the devastating warmth of Mukuro’s own mouth sucking bruises into chest. Each nearly painful suck feels like it’s hardwired to his dick, making him whimper and squirm. Desperate for friction that the Mist-pair refuses him. 

Tsuna reaches out and palms at Chrome through her own shirt as they kiss, enjoying the warm weight of her breast in his hands and the kitten soft noises of pleasure she makes in between kisses. Mukuro pulls away for a moment to make an appreciative noise at the picture his smaller bedmates make. And laughs as he twists reality again around them, leaving all three of them naked as the day they were born. 

Chrome doesn’t stop kissing him until Mukuro actual makes her. Cups her cheek and guides her with aching tenderness he shows to no one else until the mist-pair falls into each other. Tsuna knows that it is very likely the two of them might blur together, it’s happened before. The two of them morphing their separate bodies into mirror images of the other to echo the feeling they whispered to him once. How they are One-in-Two.

They don’t this time, Chrome stays Chrome and Mukuro is still Muruko. But that is fine too, Tsuna doesn’t mind indulging them in whatever form the pair is comfortable in at the moment. Male, female, both, or neither. Each is its own pleasure to enjoy.

So he rolls onto his side and slides down to put him on level with Chrome’s chest and indulges himself in lapping at her left breast, while gently circling her right nipple. Chrome is more sensitive here then Mukuro is, and Tsuna wants her to squirm in the same heated way he had been. Wanting to share that hunger with her, as Chrome’s desperation is often the fastest way to pull Mukuro in as well. 

Chrome pulls away to release a shaky moan, and Tsuna smirks as he pulls Chrome away from Mukuro’s greedy hands. Letting his own Mist secondary suffuse between the three of them in a way that always riles the male-half of the pair up. 

Chrome laughs as she is tucked under Tsuna’s body and surrenders to his assault with a happy murmur of “Bossu.”

Tsuna kisses his way down her chest, stopping to nip at her breast with enough pressure to make her wriggle in delight before moving on further. Mukuro gives a thoughtful hum and lays beside Chrome. Reaching out to kiss her again, but not touching beyond that. Tsuna is momentarily worried he’s taken too much liberty by taking Chrome away from the man, but the distress in his Sky Flames is smothered under their shared pleasure. Mukuro is simply happy to indulge is watching for the moment before pouncing. Tsuna releases the breath he was holding and continues to trail open mouth kisses down Chrome’s stomach. Laying worshipful kisses to where he knows it is only Mist constructs keeping her healthy and alive. 

Thinking of her missing organs momentarily reminds him of what Nono implied he should be doing. How he should have Chrome fulfill her _ ‘duty’  _ as his Guardian and provide him with an heir. How he should lay his child in her belly and make her suffer through months of pain on his behalf, until she likely ends up hollowed out and broken. All for the good of the Famiglia.

He pushes those thoughts aside, banishes the upsetting image and makes a vow to himself. He will not be the cause of her suffering. He will not force Chrome, or Kyoko, or Haru, or Hana - or hell - any of his Guardians and friends into baring him a child. No matter what Nono tells him to do. 

He doesn’t care that his grandfather thought it was okay to make his first Lightning birth his heir. Tsuna is not Timoteo di Vongola. He is also not Sawada Iemitsu, content to use civilians for his needs. He will not use others in the name of duty. He has built his empire on the promise of safety and care. To be the all encompassing Sky and provide what others need, instead of taking what they can give. He prides himself on this. On knowing that he gives instead of takes.

And as Tsuna settles between the pale thighs of his Mist, eagerly lapping at the warm slick her body produces with broad strokes of his tongue. An idea starts to form in his mind.

She moans and writhes at his touch. And he decides he’s happy to lay right here and indulge in her pleasure. Nono’s voice is still too loud in the back of his mind for him to feel comfortable sliding himself into her heat. But he buries the insidious voice away as her thighs clamp around his head, making him laugh even as he dedicates himself to causing her to scream her enjoyment. 

Mukuro eventually tires of watching and moves behind Tsuna. His large hands smoothing down his sides lightly enough to tickle. Which causes Tsuna to whine and try to wiggle away. His movements making Chrome gasp again. Mukuro forces him to stop moving as he grabs his hips, his hands still slightly cool.

Mukuro’s soft chuckle is Tsuna’s only warning as he feels Mist Flames invade his body and prepare him impatiently. Not that he truly needs it, his own minor Mist Flame is more than enough to ready him for what is to come. It’s almost a pavlovian response at this point if any of his Guardian’s grab at his hips for him to become slick and open for them. Even Chrome’s soft touch gets him like that - especially if she is having a day where her body is more intune with Mukuro’s.

He buries his tongue into Chrome’s slit and moans as Mukuro sinks into him slowly. Eager for the stretch and promise of finally getting some attention to where he desperately wants it. Chrome whimpers as his moans cause vibrations to echo through her body. And Tsuna makes himself focus on her, wants to give her as much pleasure as possible to make up for the words his grandfather said about her.

But it’s  _ hard _ to concentrate as Mukuro pins him and grinds into his body ruthlessly, uses him in a way the Sky adores being used. The slight friction of his cock against the sheets almost too good. He’s buried in damp curls, jaw gloriously aching from all the kisses and messy licks he lavishes Chrome with, but he can’t ignore the starbursts of pleasure that rock his body everytime Mukuro hits his prostate. 

“ _ Bossu. _ ” Chrome whimpers, thighs starting to shake and her Flames fluctuate delightfully around Tsuna’s Sky. Her soft cry of his title all the begging she needs to give him, as he can feel the request in the way her Mist twins around him imploringly, desperate for that last push to send her over the edge. Tsuna hums in acknowledgement and drags his full attention to Chrome, and away from Mukuro’s torturous grinding into him, laving attention on her clit and sucking gently in a random pattern that never fails to work on the amethyst-eyed girl. Her soft cries start to pick up, and as she grows louder. Tsuna notes that Mukuro works his hips faster in turn as well. Chrome’s pleasure winding the other up to the point he is panting where he is poised over Tsuna’s body. Red and blue eyes watching the way Tsuna works over his other half with hunger.

Chrome’s cry of completion is magnificent, as it is one of the few times she truely raises her voice above a soft whisper and Tsuna _ loves  _ the way it reverbs around his office. He will probably hear the ghost of her cry for weeks after this. But the way her Mist Flames anchor into Tsuna and Mukuro’s Flames and  _ drags _ the pair with her is even better. She pulls and twists and demands they share in the delicious echos wracking her thin frame with her. Wants them to indulge her and come.

Tsuna is more than happy to comply and comes with his own moan into Chrome’s heat, which causes the girl to pant at the additional stimulation. But Mukuro gives a strained laugh as his hips stutter at her unspoken demand, obviously intent on dragging this out. Tsuna shoves all the pleasure he’s feeling between the three of them outward, using Mukuro’s link to his Harmony to let him feel his enjoyment. Which causes Mukuro to hiss a bitten off curse and grind down in a vicious circle, and Tsuna cries out loudly again as warmth fills him. 

Tsuna moans low, and blushes brightly as he is viciously reminded of his sudden epiphany from earlier. Mukuro’s come is warm inside him and heavily laden with Mist Flame that his own body eagerly absorbs. It will give him a small boost to his own Mist Flame secondary for a little bit, but it is temporary. Only liable to last a few hours at the most he knows from prior experience. He’ll need longer then that for his crazy idea to work.

He whimpers slightly as the male-half of his Mist set pulls out, and let’s Chrome pull him up her body so they can share a sloppy kiss while Mukuro flops to the side. Running his chilly palms over both their overheated bodies and watching them kiss with a satisfied smirk on his face. 

Tsuna break their kiss when it becomes hard for him to keep from flopping down onto Chrome and crush her, his arms a little wobbly from holding himself up the whole time. Instead he falls to the side of the bed not occupied by Mukuro and sighs softly. Feeling both relaxed and horribly embarrassed at where his mind is starting to drift too. Especially as he feels Mukuro’s cum starting to slide down his thighs. He could use his own Mist Flames to banish it away, but he is embarrassingly hesitant to do so. 

After all, if this plan of his is going to come to fruition. He’s going to have to get used to the feeling, isn’t he? 

**Author's Note:**

> Don't listen to Hozier folks, you'll be possessed by a Fae and write oral and threesomes.
> 
> And if for one good-god-damned second you thought I wouldn't involve overly complex Flame-based headcannons in my porn, you are wrong. Buckle up, we have nonsense to indulge in.
> 
> If any errors are seen lemme know. This bad-boy is self-edited.


End file.
